Ok, so you'll never use crossbows, IF they're in the game... but how will it hurt you in any way that crossbows are ingame? Just because Nords aren't that smart doesn't mean the dwemers crossbows magicelly disapeared from their ruins, now do it?
When I'd stumble accross the crossbow I would feel like this:
Imagine Lord of the ring, the movie. You're used to this kind of medieval fantasy with magic and fictional races etc. Then out of no where an enemy unit armed with light sabers attack.. :confused:
No matter how much Crossbows would or wouldn't be part of previous lore, it doesn't mean it has to be in the game just because some crossbows would have been left behind by the Dwemer and no matter if crossbows were in Morrowind, I don't think it fits Fantasy in any way, it's just one step away from hand portable cannons (hand guns) and muskets, or at least that's how I think about it. There will always be Morrowind fans who scream out loud that they want to find crossbows in Skyrim (light sabers in LoTR), but I'll just get puzzled by them none the less.